Spring Steel Strip for Roller Shutter Doors 1.Material: 65, 70, 75, 85, 65Mn, etc 2.Thickness ... .Width:30mm-355mm Specification of Spring Steel Strip for Roller Shutter Doors :1.Material: 65, 70, 75, 85, 65Mn, 55SiMnV, 60Si2MnA, ... general engineering applications. It is suitable for applications that require high strength and toughness. Typical applications include crankshafts, steering knuckles, ...